I liked a lot of this episode. Hoshino's flashback being at the start was good and it was great seeing her legitimately serious. Everything tying together with this very much being an episode about Hoshino. Well about her while she's not necessarily in every scene. The Gehenna stuff was actually really nice. Some nice flashes of how absolutely intense Hoshino was and that you can't judge people based on what you see on the surface. And I thought it was pretty fun how Hina wasn't giving Ako a break. If she wants to exaggerate then she better watch out for actually having to live up to that! Hina probably was legitimately upset at how Ako put everyone into danger on a reckless mission like that.
PS68 is always a goofy and enjoyable bunch. Good on them for dropping off that money since...they did screw up there. And fitting that they had to bail out on their base. Haruka definitely needed that moment of apologizing since she messed up the most out of anyone.
In terms of Sensei I'm only going to be worried if they have Shiroko filling all of Sensei's big moments coming up. Then we could start wondering about what they are doing here. But for now I'm mostly ok with what they are doing. Since Sensei only gets so many big moments in this first arc. Having Shiroko meet with PS68 is fine for me.
Ending was certainly something interesting to read into... And that's about more than just Shiroko's shower scene
! Although honestly between that and Hina's thighs this episode managed to find the time for some fanservice. But beyond that the scene was pretty darn tense. A bird flew in and broke some stuff. Probably just foreshadowing for how things are getting serious, but I guess we'll see.